The emigration of leukocytes from the pulmonary capillaries into the parenchyma is a critical step in the inflammatory response within the lung. Neutrophil emigration in response to stimuli within the lung occurs through two pathways, one that requires the leukocyte adhesion molecule, CD11/CD18 and one that does not. Which pathway is utilized depends on the stimulus. Stimuli that elicit CD18-dependent neutrophil emigration induce upregulation of the ligand, ICAM-l mRNA and protein on endothelial cells while stimuli that elicit CD18-independent emigration do not, suggesting that the regulation of ICAM-l expression determines the selection of adhesion pathway. Because ICAM-l is regulated by cytokines including interleukin-l and tumor necrosis factor-alpha, which adhesion pathway is utilized may be determined by the balance of cytokines produced in response to a particular stimulus. The proposed studies address two questions, what determines whether the CD18-dependent or -independent adhesion pathway is utilized and whether members of the selectin family of adhesion molecules mediate CD18-independent emigration. The working hypotheses are 1) the balance of cytokine production and function in response to a particular stimulus determines which adhesion path way will be utilized, and 2) CD18-independent neutrophil emigration is mediated through selectins. The studies proposed in Aim #1 will determine both the expression of ICAM-l mRNA using Northern blots and in situ hybridization and the function of ICAM-l using ICAM-l deficient mice, anti-sense oligonucleotides, or anti-ICAM-l antibodies by quantitating neutrophil emigration in acute and chronic pneumonia induced by stimuli that elicit either CD18-dependent or -independent emigration, as well as granulomatous inflammation and interstitial fibrosis. The studies proposed in Aim #2 will determine the expression and function of cytokines produced in response to each type of stimulus by measuring the concentrations of pro- adhesive and chemotactic cytokines in the airspaces and by inhibiting their function using either antibodies or soluble receptor-IgG chimera. The expression of E-selectin and its receptor (Aim #3), as well as P- selectin and its receptor (Aim #4) will be localized and quantitated using light and ultrastructural immunohistochemical techniques. The function of these two selectins during acute inflammation will be determined using anti-rabbit E-selectin antibodies, soluble E-selectin-lgG or P-selectin- IgG chimera, and P-selectin-deficient mice. These studies will help to understand the functions of cytokines produced in the lung, the selection of adhesion pathways, and the molecules mediating CD18-independent adhesion. They will investigate new approaches to anti-adhesion molecule and anti-cytokine therapy focussed on increasing leukocyte emigration when it is beneficial and inhibiting this process when it contributes to tissue injury.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL052466-04
Application #
2460047
Study Section
Lung Biology and Pathology Study Section (LBPA)
Project Start
1994-08-01
Project End
1998-07-31
Budget Start
1997-08-01
Budget End
1998-07-31
Support Year
4
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Harvard University
Department
Public Health & Prev Medicine
Type
Schools of Public Health
DUNS #
082359691
City
Boston
State
MA
Country
United States
Zip Code
02115
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Gomez, John C; Dang, Hong; Martin, Jessica R et al. (2016) Nrf2 Modulates Host Defense during Streptococcus pneumoniae Pneumonia in Mice. J Immunol 197:2864-79
Gomez, John C; Yamada, Mitsuhiro; Martin, Jessica R et al. (2015) Mechanisms of interferon-? production by neutrophils and its function during Streptococcus pneumoniae pneumonia. Am J Respir Cell Mol Biol 52:349-64
Yamada, Mitsuhiro; Gomez, John C; Chugh, Pauline E et al. (2011) Interferon-? production by neutrophils during bacterial pneumonia in mice. Am J Respir Crit Care Med 183:1391-401
Gomez, John C; Doerschuk, Claire M (2010) The role of CD18 in the production and release of neutrophils from the bone marrow. Lab Invest 90:599-610